1. Field of the Invention
The present invention relates to a mount for positioning a photodetector on an optical apparatus, and more particularly to a mount for adjusting the position of a photodetector used, for example, in an optical disk drive in X and Y directions in the magnitude of a few micron respectively in order to precisely align the center of a laser beam and the center of the photodetector at the time of or after fixing the photodetector to the body of the optical disk drive. The mount of the present invention can also be used to adjust the position of a photodetector used in the other detectors or sensors which require fine adjustment in X or Y direction or in both the X and Y directions by order of few microns magnitude.
2. Information Disclosure Statement
For conventional methods of adjusting the position of a photodetector of an optical disk drive or a compact disk drive, there are two methods: first, a method of bonding a photodetector directly to a base plate of an optical device with bond after adjusting the photodetector using a special jig, and second, a method of fixing a photodetector to a base plate of an optical device with a set screw after adjusting a position of the photodetector by adjusting a reference plate attached to the photodetector with a special jig.
Because the first adjusting method mentioned above among the conventional methods is to fix the photodetector to the base plate of the optical device by using adhesives, there is a problem of poor thermal stability. That is, when the temperature of the mount and ambient environment rise due to the laser beam used in the optical device, the adhesive strength of the adhesive is weakened and it causes the deformation of the mount regarding the body of the optical device. Once the above condition is occurred, readjustment of the mount is impossible at a later time since the adhesive loses its adhesive strength between the mount and the body of the optical device.
In the other method mentioned above, it is possible to readjust the mount at a later time by using a set screw; however, because a range in which the screw moves is too large in comparison with a range which is required for fine adjustment of the mount within the range of several micron, a precise adjustment is very difficult. Therefore, a precise and special jig is required for precisely adjusting the mount to the body of the optical device in the process of fixing the mount to the body of the device. This nevertheless is an elaborate operation, and increases costs and time for mounting the mount to the body of the optical device.
Therefore, it is desirable to provide a mount or an apparatus which can adjust the photodetector precisely without a special exclusive jig during the operation of fixing the mount to the body of the optical device and readjusting the position of the mount after such fixing operation.